a. Field of the Invention
This invention relates generally to medical instruments, and, more specifically, to navigating a surgical device toward a target organ in the body of a patient.
b. Background Art
Medical procedures are known in which a surgical device is inserted into a patient's body near a target area, the heart for example, to implant cardiac rhythm devices, replacement heart valves, and the like. In a typical subclavian procedure, a physician uses a surgical needle to puncture the subclavian vein in order to enable access for a guide wire to the heart. In one example procedure, transapical aortic valve implantation (TAVI), this approach requires the insertion of the surgical needle directly into the apex of a beating heart. Such punctures may be complicated in some cases, and involve the risk of lung puncture, as well as other complications. In order to reduce these risks, it is desirable for the physician to know the location and orientation of the tip of the surgical needle, and then to visualize the guide wire as it is navigated within the body of the patient, in order to minimize physical injury to the tissues surrounding the desired organ and ensure that the guide wire reaches the target. Methods for determining the location and orientation of surgical devices are known in the art.
One such method utilizes a fluoropaque marker (e.g., a metallic coil, an active impedance-sensing electrode, and the like) coupled to the tip of the needle and another sensor wound around the tip of a guide wire inserted through the needle and used to deliver a cardiac rhythm device, replacement heart valve, etc. to the desired location within the patient's body. The sensors are visible when exposed to a field of ionizing radiation (e.g., x-rays). A display outputs a visual representation of the needle and the guide wire inside the patient's body based on the position of the sensors under the radiation.
However, these methods require that radiation be used during the entire procedure in order that the sensors generate output indicative of the position of the needle and guide wire throughout the procedure. Accordingly, the physician's hands also must be exposed to radiation during the entire procedure. Even after the needle has been placed, the physician's hands are still exposed to radiation while inserting the guide wire through the needle and navigating the guide wire toward the heart.
Systems and methods are desired which provide the physician with a visualization of the location and orientation of the surgical needle within the body of the patient, in order to minimize physical injury to the organs and surrounding tissues. Systems and methods are also desired which provide the physician with a visualization of the location and orientation of the guide wire within the body of the patient, in order to properly position the guide wire near the target organ. Systems and methods are also desired to achieve these objectives while reducing or altogether eliminating the physician's exposure to radiation during a medical procedure.